<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .clearfix::after{
            content: "";
            display: block;
            clear: both;
        }
        .box{
            width: 800px;
            /* height: 600px; */
            background-color: skyblue;
            margin: 0 auto;
            border: 10px solid #000;
        }
        .box .item{
            width: 190px;
            height: 200px;
            background-color: khaki;
            float: left;
            margin: 5px;

        }
    </style>
</head>
<body>
    <div class="box clearfix">
        <div class="item">1</div>
        <div class="item">2</div>
        <div class="item">3</div>
        <div class="item">4</div>
        <div class="item">5</div>
        <div class="item">6</div>
        <div class="item">7</div>
        <div class="item">8</div>
        <div class="item">9</div>
        <div class="item">10</div>
    </div>
</body>
</html>